{"common":{"save":0,"post_id":"6493","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"6850","mon_id":"1158767","chapter_id":"1158895","post_id":"6493","question":"<p>M\u1ed9t h\u1ed9p ch\u1ee9a 4 cái th\u1ebb \u0111\u01b0\u1ee3c \u0111ánh s\u1ed1 1, 2, 3, 4. L\u1ea5y ng\u1eabu nhiên 2 th\u1ebb. Tính xác su\u1ea5t c\u1ee7a bi\u1ebfn c\u1ed1 A: ‘’ <span style=\"color:#2980b9;\">t\u1ed5ng các s\u1ed1 trên hai th\u1ebb là s\u1ed1 ch\u1eb5n<\/span>’’ .<\/p>","options":["<meta charset=\"utf-8\" \/><b id=\"docs-internal-guid-5c94cbe4-7fff-7c14-24d6-f7757e29618a\">A. <span class=\"math-tex\">$\\dfrac{5}{6}$<\/span><\/b>","<b id=\"docs-internal-guid-5c94cbe4-7fff-7c14-24d6-f7757e29618a\">B. <span class=\"math-tex\">$\\dfrac{1}{6}$<\/span><\/b>","<b id=\"docs-internal-guid-5c94cbe4-7fff-7c14-24d6-f7757e29618a\">C. <span class=\"math-tex\">$\\dfrac{1}{2}$<\/span><\/b>","<b id=\"docs-internal-guid-5c94cbe4-7fff-7c14-24d6-f7757e29618a\">D. <span class=\"math-tex\">$\\dfrac{1}{3}$<\/span><\/b>"],"correct":"4","level":"2","hint":"","answer":"<p>Không gian m\u1eabu <span class=\"math-tex\">$\\Omega=\\{(1,2);(1,3);(1,4);(2,3);(2,4);(3,4)\\}$<\/span> nên <span class=\"math-tex\">$n(\\Omega)=6$<\/span>.<\/p><p>Li\u1ec7t kê ta có: <span class=\"math-tex\">$A=\\{(1,3);(2,4)\\}$<\/span> nên n(A) = 2.<\/p><p>V\u1eady <span class=\"math-tex\">$P(A)=\\dfrac{n(A)}{n(\\Omega)}=\\dfrac{2}{6}=\\dfrac{1}{3}$<\/span><\/p><p>Ch\u1ecdn <span style=\"color:#16a085;\"><b id=\"docs-internal-guid-5c94cbe4-7fff-7c14-24d6-f7757e29618a\">D. <span class=\"math-tex\">$\\dfrac{1}{3}$<\/span><\/b><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-05-30 02:57:35","option_type":"math","len":0},{"id":"6854","mon_id":"1158767","chapter_id":"1158895","post_id":"6493","question":"<p>Trong m\u1ed9t tr\u01b0\u1eddng THPT, kh\u1ed1i 12 có 280 h\u1ecdc sinh và kh\u1ed1i 11 có 325 h\u1ecdc sinh và kh\u1ed1i 10 có 375 h\u1ecdc sinh. Nhà tr\u01b0\u1eddng c\u1ea7n ch\u1ecdn ba h\u1ecdc sinh \u0111i d\u1ef1 tr\u1ea1i hè thành ph\u1ed1. Tính xác su\u1ea5t c\u1ee7a bi\u1ebfn c\u1ed1 A: "<span style=\"color:#2980b9;\">ba h\u1ecdc sinh \u0111\u01b0\u1ee3c ch\u1ecdn \u1edf c\u1ea3 ba kh\u1ed1i<\/span>".<\/p>","options":["<meta charset=\"utf-8\" \/><b id=\"docs-internal-guid-c2175a87-7fff-702e-f5a6-1959dc8176cf\">A. <span class=\"math-tex\">$\\dfrac{7 06250}{819273}$<\/span><\/b><b> <\/b>","<b id=\"docs-internal-guid-c2175a87-7fff-702e-f5a6-1959dc8176cf\">B. <span class=\"math-tex\">$\\dfrac{7 06250}{7819273}$<\/span><\/b><b> <\/b>","<b id=\"docs-internal-guid-c2175a87-7fff-702e-f5a6-1959dc8176cf\">C. <span class=\"math-tex\">$\\dfrac{17 06250}{7819273}$<\/span> <\/b>","<b id=\"docs-internal-guid-c2175a87-7fff-702e-f5a6-1959dc8176cf\">D. <span class=\"math-tex\">$\\dfrac{17 0625}{7819273}$<\/span><\/b>"],"correct":"3","level":"2","hint":"","answer":"<p>M\u1ed7i cách ch\u1ecdn 3 h\u1ecdc sinh \u0111i d\u1ef1 tr\u1ea1i hè thành ph\u1ed1 là m\u1ed9t t\u1ed5 h\u1ee3p ch\u1eadp 3 c\u1ee7a 980.<\/p><p>V\u1eady s\u1ed1 ph\u1ea7n t\u1eed c\u1ee7a không gian m\u1eabu là <span class=\"math-tex\">$n(\\Omega)=C_{980}^3=156 \\space 385 \\space 460$<\/span><\/p><p>\u0110\u1ec3 ba h\u1ecdc sinh \u0111\u01b0\u1ee3c ch\u1ecdn \u1edf c\u1ea3 ba kh\u1ed1i thì<\/p><p>+ ch\u1ecdn m\u1ed9t h\u1ecdc sinh kh\u1ed1i 12 có 280 cách.<br \/>+ ch\u1ecdn m\u1ed9t h\u1ecdc sinh kh\u1ed1i 11 có 325 cách.<br \/>+ ch\u1ecdn m\u1ed9t h\u1ecdc sinh kh\u1ed1i 10 có 375 cách<\/p><p>Theo qui t\u1eafc nhân, ta có n(A) = 280 . 325 . 375 = 34 125 000.<\/p><p>V\u1eady <span class=\"math-tex\">$P(A)=\\dfrac{n(A)}{n(\\Omega)}=\\dfrac{34125000}{156385460}=\\dfrac{17 06250}{7819273}$<\/span><\/p><p>Ch\u1ecdn <span style=\"color:#16a085;\"><b id=\"docs-internal-guid-c2175a87-7fff-702e-f5a6-1959dc8176cf\">C. <span class=\"math-tex\">$\\dfrac{17 06250}{7819273}$<\/span><\/b><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-05-30 03:06:13","option_type":"math","len":0},{"id":"6857","mon_id":"1158767","chapter_id":"1158895","post_id":"6493","question":"<p>M\u1ed9t h\u1ed9p ch\u1ee9a 4 cái th\u1ebb \u0111\u01b0\u1ee3c \u0111ánh s\u1ed1 1, 2, 3, 4. L\u1ea5y ng\u1eabu nhiên 2 th\u1ebb. Tính xác su\u1ea5t c\u1ee7a bi\u1ebfn c\u1ed1 A: ‘’ <span style=\"color:#2980b9;\">t\u1ed5ng các s\u1ed1 trên hai th\u1ebb là s\u1ed1 l\u1ebb<\/span>’’.<\/p><p><meta charset=\"utf-8\" \/><\/p>","options":["<strong>A. <span class=\"math-tex\">$\\dfrac{5}{6}$<\/span><\/strong>","<strong>B. <span class=\"math-tex\">$\\dfrac{1}{3}$<\/span><\/strong>","<strong>C. <span class=\"math-tex\">$\\dfrac{2}{3}$<\/span><\/strong>","<strong>D. <span class=\"math-tex\">$\\dfrac{1}{6}$<\/span><\/strong>"],"correct":"3","level":"2","hint":"","answer":"<p>Không gian m\u1eabu <span class=\"math-tex\">$\\Omega=\\{(1,2);(1,3);(1,4);(2,3);(2,4);(3,4)\\}$<\/span> nên <span class=\"math-tex\">$n(\\Omega)=6$<\/span>.<\/p><p>Li\u1ec7t kê ta có: <span class=\"math-tex\">$A=\\{(1,2);(1;4);(2;3);(3,4)\\}$<\/span> nên n(A) = 4.<\/p><p>V\u1eady <span class=\"math-tex\">$P(A)=\\dfrac{n(A)}{n(\\Omega)}=\\dfrac{4}{6}=\\dfrac{2}{3}$<\/span><\/p><p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>C. <span class=\"math-tex\">$\\dfrac{2}{3}$<\/span><\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-05-30 03:11:15","option_type":"math","len":0}]}